Stoker



Oct. 17, 1933. I H s ER I 1,931,172

I STOKEH Filed Feb. 1, 19:50 10 Sheets-Shee t 2 I I ENTOR A TTORNEY-i Oci. 17, 1933. H. M. SWiNDLER 1,931,172

STOKER Filed Feb. 1, 1930 10 Sheets-Sheet 3 1N TOR Oct. 17, 1933. M SW'INDLER 1,931,172

STOKER Filed Feb. 1, 1930 10 Sheets-Sheet 4.

Jiq4.

" ED //////V A TTORNEY-S' 1933- H. M. SWINDLER 31,172

A TTORNE Y6 Oct. 17, 1933. swm 1,931,172 I STOKER Filed Feb. 1, 1930 l0 Sheets-Sheet 6 IN ENTOR A TTORNE Y3 Oct. 17, 1933. H M. SWINDLER STOKER Filed Feb. 1, 1930 10 Sheets-Sheet 7 1 rgvroR A TTORNEYJ BY [w Oct. 17, 1933. H, swmD 1,931,172

STOKER Filed Feb. 1, 1930 10 Sheets-Sheet 8 A TTORNE Y6 IZVEMOR CZ STOKER Filed Feb. 1, 1930 10 sheets-sheet 9 A ITORNEYS STOKER Filed Feb. 1, 1930 10 Sheets-Sheet 1O llll CU A TTORNEYJ ash, and will provide means foi fladequately coolg air or apportioning it to the respective sides of for creating a suitable draft over thefire' bed by air flowing under the distributing plates.

Patented Oct. 17, 1933 1,931,172 s'roKEa Harry MaSwindler, Dayton, Ohio, assignorlto The James Lefit'el & Company, Springfield, Ohio, a;

, corporation of Ohio' Application February 1, 1930. Serial No. 425,201

34 Claims.

My invention relates to stokers and in particu-; lar to stokers'ior' Scotch marine boilers.

It is myobject to provide a stoker which" can be utilized in the limited area and peculiar construction of a Scotch marine boiler wherein the fire box is completely surrounded by water of the boiler. A

It is my object to provide a stokerthat will fit within the limited the box of such a boiler;.will provide means for accumulating andstorin'g the ing the entire structure, preferably from a single source.

It is a further object of my invention to provide a systemof air chambers for balancing the the nte box according to the demands for air therein.

It is a further object to utilize the air for cooling the rivet heads, for cooling the fire doors and and through the top of the fire box in order to cause adequate and uniform burning of the fuel throughout the length of the retort.

It is a further object to provide an arrange 'ment of tuyeres such as a clinker pocket is formed at eachside of the grate away'fro'm the coal feeding retort which allows ash and Cinders tobaccumulate without fouling of the air ports with fused ash.

It 'is a further object'to provide positive air circulation under the distributing plate, to provide air cooling and to scavengecoal sittings to allow free and unobstructed movement of the plate as well as air cooling the rivet projections It is a further object to provide such air flow, which has then been thus preheated to assist in the combustion of volatile gases distilled at the front part of the furnace. I

It'is a further object to provide a bridge wall built'in as a part of the Stoker-with removable brick held in place by a common assembly means.

It is a further object to provide means of alignirig the tuye'res, spacing them from the retort, positioning the retort an'dformingan air delivery chamber and an air return chamber for cooling the rivet heads, all by a single, radial, detachable means Within the fire box. It is a further object to provide streamline passageways in the tuyeres so arranged as to be self-cleaning to prevent'the choking of the passageways by fuel whether in lump or in powdered condition.

It is a further object to provide'seale'd joints to prevent the sitting of coal-dust and the choking of the passages. Referringto the drawings:

Figure 1 is a vertical'section through the end of the boiler and stoker mechanism;

Figure 2 is a section on the line 2'--2 of Fi ure-1; Figure 3 is a similar View to Figure 1 showing the remainder of the boiler and Stoker in section: Figure is a section on the line 4--4 of Figurei'; Figure 5 is a sectionon'the' line-5-5 of Figure 1 Figure 6 is a section on the line 6- 6 of Figure 1 Figure 7 is a section on the line 77 of Figure 3; Figure 8 is a section on the line 8--8 ofFigure 3; Figure 9 is a section or the line 9-9 of Figure 3;: Figure 10 is a detail View of the air control and damper mechanism; I Figure 11 is a section onthe line --11---11 01 Figures 1 and 3.

outer Referring to the drawings in detail,1 indicates the'outside shell of the boiler'having the moose and the cylindrical fire box 3, which is com pletely surrounded by water indicatedat 4';

The limited area of this" fire box has hereto fore been regarded as making itimpossible to provide an automatic, continuous operation of a stoker, which would be self cleaning of ash' and =0 clinker, that could be readily accessible and which could be removable asa unit or'iin seetions. The cylindrical fire box' 3 is attached tome outside boiler wall 1 by alp'lurality or riv ts-5.

The heads otthese rivets at the entrance tdthe fire box project inwardly as at 6= into the the Within the fire box is mounted a retort for receiving the coal, such retort'being" comprised of. side walls 7 andB anda sloping reafendwallfi. 'Ihesi'de walls Tand 8' are extendedbeyond the rear wall 9 and are joined together by a vertical wall hereinafter described. Thel'egsw pr'ovi'de'a support for the retort upon the-bottom of the firebox and rest on the fire box between the it rivet heads 6.

The bottom of the retort has a shouidenon either side thereof" as at llffor receiving the edges of the reciprocating pusher plate 12. This pusher plate is provided with pusher shoulders 13 f that are detachably mounted thereon by the bolts 14. The fOrwairdend-of'the pusher plate- 12 slidably rests upon a horiz'ontalportion 1 5 that 7 forms an under bottom ofthe' retort and is a continuation of the rear wall 9. Suitable ribslfi are provided on the bottom of thepusher plate-12 I for its adequate reinforcement;

The upper edges of the retort are provided with a laterally extend'ing flange which serves as the inner support for the tuyres 18. The tuyeres comprise a body having an inner jaw 19, one face of which 20 rests upon the flange l7 and the other portion of which 21 extends beneath the flange.

The retort face of the tuyeres is provided with a plurality of inwardly extending and upwardly directed openings 22, the inner ends of which at 23 are directed downwardly and are separated by streamline partitions 24. These. partitions are directed from the retort end at an angle to the inward movement of the coal along the retort so that the inner ends of the passageway are closer to the doors of the fire boxthan the retort ends of the passageways, thus making thetuyeres self cleaning.

The cap of the tuyere is formed with an arcuate.

inner end 25 which proceeds from the inner surface adjacent the fuel retort upwardly and then downwardly towards the wall of the fire box forming an arcuate. bed 26 for receiving the ash and clinker, which is rolled overand pushed to the outer wall of the fire box out of the way as the fuel is moved from the retort by the pusher and is consumed.- The outer ends of these tuyeres are arcuate at 27 to fit the inside of the fire box and are provided with depending ribs 28 which rest upon the horizontal plate 29 of the arcuate spacer 30. This spacer is provided with a vertical flange 31 which engages the vertical face of the side walls '7 and8 of the retort respectively.:- V 1 b .The'shoulders 32 of arcuate shape are located within this arcuate spacer 30, the shoulders 32 a being formed on the wall 45 and having cut away portions in one of them as at 32a for clearing the higher.- rivet. 322) at the overlapping of the fire box wall 3. The space thus formed as at 33 and 34 is utilized for the air supply through the i openings 22 in the tuyeres for the combustion of the fuel. As will behereinafter described, the return air returns from the spaces 33 and 34 through 36a to the space 37 whence the air proceeds forwardly underneath the retort to the front of theboiler. a

Bridge wall construction These tuyeres are held together by the longitudinal bolts 38 that extend from the front' of the retort to the rear. 7 ,Suitably formed tuyere blocks form the rear end of the furnace as at 39 having an arcuate face 40. The rear ends of these blocks rest upon their shoulders 41 on the ledge 42 of the angular transverse plate 43 which is mounted upon the shoulder 44- of the supporting wall 45. This plate is provided with angular bridge wall brackets 46 which retain between the faces 47 and 48 the bridgewall blocks 49. An angular retaining plate 50- overlaps a shoulder 51 ofsuch blocks retaining them in position.

The bolts 38 enter the supporting wall 45. m The bolts 45a join the plates 43 and 45.' The bolts 46a join the plates 46 and 45.

Air' rte-circulation construction .into'theannular passageways 53 formed by annular flanges 61a on the lower fire box cover 61 and by annular sections 53a bolted into position by the bolts 531) on either side of the retort. This annular passageway 53 isspaced from the fire box 3 for conveying the return air to points above the annular filler for the delivery of air through the openings 54 into the top of the fire box around its inner margin, thus cooling the upper rivets 6 and driving the volatile gases, together with the air issuing through the ports 60, from adjacent the fire door. Filler blocks 57a; rest on the bottom plate 57 and sections 53a.

The air issuing through the ports is supplied from the air supply spaces 33 and 34 through the. passageways 55.. The lower part of these passageways is formed byv the cover plate 56 mounted onthevretort. The under side ofv this cover plate has an inwardly and upwardly extending tapered face for directing the coal. in- V to thespace between the tuyeres. On top of this cov'er plate rests the bottom 57of an annular filler which has a flange 58 towards the furnace door anda plurality of spaced ribs 59 to form with plate 56 upwardly extending openinigs 60 for the escape ofair. The upper part of the passageways 55 is formed .by the bottom plate 57.} b

p .The annular. filler abuts against the p1ate62 while the lower plate 61 with the angular ring plate 63 in cooperation with the retort forms the remainder ofthelclosure for the lower half of the fire box. Thebolts, 61b hold the ring plate 61 on the fire box 3. h I

The plate 62 receives the respective door halves 64 and 65 that are quadrant-shaped andwhich are hinged along theline 66. Theyare Supp rt, ed on hinges comprising straps 6'7 and eyes 68 mounted on the hingerod 69, the upper end of which is detachably mounted in theoutwardly extending slotted lug 70. It isretained therein by the cross pin 71. The lower end of the hinge pin- 69'rests in a slot '72 of a cover plate 73. These doorsare provided ,with internally disposed ribs '74 for strengthening purposes and to support the fire bricks.

The doors are held'in latched closed position by the pivoted latch members '75 pivoted at 76 which have latching heads 77. These heads are provided with a'cam face 78 which is adapted to be engaged by the cam nose 79 of the bell crank lever 80 pivoted on the doors at 81. This lever isprovidecl with a handle '82. Upon lifting the handle, the nose 79 depresses the latch '78 freeing it from the door and upon pulling the'handle outwardly the door will swing outwardly onits hinge bolt 69. I, I

' Pusher ram construction application. It is operated by the handle 88 operating the hopper support 89 which slides between the shouldersQO. Y

The space beneath the reciprocating pusher 12 and 83 as at 91 can be cleaned of any accumulation of dust by the actuation of the trap door 92 which is pivoted at 93.

The ram 83 is connected by a pitman 94 to a crank 95 that is suitably actuated through amotor operating the gear within the gear box 97. This gearing and operating mechanism 'for the ram is the subject of said co-pending application and'is there described indetail and claimed.

' Air delivery system A fan 98 driven by the motor'96 which also drives the ram delivers air into the following air duct system which in turn distributes it to the main air passageways 33 and 34 beneath the tuyeres.

The fan 98 supplies air to the duct 99 which is controlled by the damper or gate 100 through an exterior locking nut 101, thus proportioning the amount of air that will be delivered-through the respective passageways 102 and 103 that communicate respectively to the air passageways 33 and 34.

It will be noted that by streamlining the fins forming the air ports in the tuyeres that I amenabled to secure greatly increased results from a given air pressure. By directing theair inthe line of movement of the coal, there is no jamming of the air ports which are thus self-cleaned from the fuel.

It will be understood that I desire to comprehend within my invention such modifications as maybe necessary to adapt it to varying condia bridge wall carried by said retort.

2. In combinatioma boiler, a circular fire box therein, a retort on the bottom of said box, tuyeres supported by said retort and the box walls, a common detachable means aligning said tuyeres and connecting them to the fire box, and a bridge wall carried by said retort, said detachable means aligning the tuyeres and also serving to align said bridge wall.

3. In combination, a boiler, a circular fire box therein, a retort on the bottom of said box, tuyeres supported by said retort and the box walls, a supporting wall carried by said retort, a bridge wall bracket on thesupporting wall, and bridge wall blocks supported by the bracket.

4. In combination, a boiler, a circular firebox therein, a retort on the bottom of said box,

tuyeres supported by said retort and the box 'walls, and a spacer plate'on either side of said retort engaging said retort at one end and the outer ends of the tuyeres at the other end, whereby an air chamber is formed beneath the tuyres on either side of the retort, means for forming an air chamber at the inner end of the retort between the bottom of the retort and the fire box, said air chamber having ports communicating with the chambers on either side of the. retort, and means to space said retort from the bottom .of the fire box .for forming a return passageway for air from said air chamber to the front of the boiler. A

5. In combination, a boiler, a circular fire box therein, a retort on the bottom of said box, tuyeres supported by said retort and the box walls, and a spacer plate on either side of said retort engaging said retort at one end and the outer ends of the tuyeres at the other end, whereby an air chamber is formed beneath the tuyres on either side of the retort, means for forming an air chamber. at the inner end of the retort between the bottom of the retortand the fire box,

said 'air chamber having ports communicating with the chamberson either side of the retort} means to space said retort from the bottom of the fire box for forming a returnpassageway for air from said air chamber to the front: of the boiler,

and ports in said means spacingthe retort'from' the fire box at the front of the firebox" whereby the air is delivered around the front end of the fire box between it and the sides of the retort;-

6. In combinationa boiler, a circularfire box I therein, a .retort' on the bottom of said box, tuyeres supported by said retort and the box walls, and a spacer plate on either side of said retort engaging said retort at one end and' the outer ends of the tuyeres at the other end, wherebyan air chamber is formed beneath the tuyeres on either side of the retort, means for forming an'air' chainher at the inner end of the retort between the bottom of the retort and the firebox, said air chamber having ports communicating'with the chamberson either side of the retort, means to space said retort from the bottom of the firebox for forming a return passageway for air from said air chamber to the front of the boiler, ports in said means spacing the" retortfroin the {fire box at the frontof theffire box whereby the air is delivered around the front end of the fire box between it and the sides of the retort,and means r of delivering said air at'points above the retort adjacent the front of the boiler.

7. In combination, a boiler, a circular-fire box therein, a retort on the bottom of said box, tuyeres supported by said retort and the box walls, and a spacer plate on either side of said retort engaging said retort at one end and the outer ends of the tuyres at the other end, whereby an air chamber is formed beneath the tuyeres' on either side of the retort, means for" forming an air chamber at theinner end'of the retort between the bottom of theretort and the fire box, said air chamber having ports communicating with the chambers on either side of the retort, means to space said retort from the bottom of the fire box for forming areturn passageway for'airifrom said air chamber to the frontof the boiler, ports in said means spacing the retort from the fire box at the front of the firebox whereby the air is delivered around the front end of the firebox between it and the sides of the retort, and means of delivering said air at points above the retort adjacent the front of the boiler, said means com prising a retort cover plate, an annular member spaced therefrom to form ports at the rear edges thereof between it and the cover plate.

8. In combination, a boiler, a circular fire box therein, a retort on the bottom of said box, tuyres supported by said retort and the box walls, and a spacerplate on either side of said retort'engaging said retortflat one end-and the outer ends of the tuyeres' at the other 'end, whereby an air chamberis formed beneath the tuyeres on either side of the retort, means, for forming an air chamber at. the innerj end of the retort between the bottom of the retort and the fire box," said air chamber "having ports comfront of the boiler, ports in said means spacing the retort from the fire box at the front of the fire box whereby the air is delivered around the front end of the fire box between it and the sides of the retortfmeans of delivering said air at points above the retort adjacent the frontof the end wall and retort. I r V 13. In combination in a boiler, a fire box, a

. the top thereof.

boiler, saidmeans comprising av retort cover plate, an annular member spaced therefrom to form ports at the rear edges thereof between it and the cover plate, and means between s'aid'an nular member and the top of the fire box for delivering air vtherebetw'een at that point. I 9. In combination, a firebox, a retort therein, a pusher for supplying fuel through and over the sides of the retort, tuyeres supported by the fire box and the retort forming airchambers on either side of the retort below the tuyere's within the fire box, means of delivering air thereto, and means of returning air beneath the retort from the inner end to the fire door end of thefire box. 10. In combination, a fire box, a retort therein, a pusher for supplying fuel through and over the sides of the retort, tuyres supported by the fire box and the retort forming air chambers on either side of the retort below the tuyeres within the fire box, means of delivering air theretoQmeans of returning air beneath the retort from the inner end'to the fire door end of the firebox, and means of delivering said air at the front of the fire box from beneath the retort to 7 a point above the retort.

11. In combination, a fire box, a retort therein, a pusher for supplying fuel through and over the sidesof the retort, .tuyeres supported by the fire box and. the retort forming air chambers on either side of the retort below the tuyeres within the fire box, means of delivering air thereto, means of returning air beneath the retort from the inner end to the fire door end of the fire box, and means for delivering said air at the front of the fire box from beneath the retort to a point above the retort, said means for delivering said aircomprising a delivery means just above the retort'and' an second delivery means at the front of the fire box just beneath 12. In combinationin a boiler, a fire box, a retort supported thereby, tuyres supported by the fire box and the retort, an end wall, supported on the inner end 'of said retort, means for supporting said tuyres in alignment on said of said retort having'return air passageways communicating with a space between it and the fire box, andmeans to deliver air at the front of the retort from said space.

14. In combination in a boiler, a fire box, a retort, an end plate on the inner end thereof, spacer plates mounted on either side of said re'- tort on said endplate, tuyres bridging said spacer plates and retort walls to form air chambers on either side of the retort, the innerend of said retort having return air passageways communicating with a space between it and the fire box, means to deliver air at the front of the retort. from said space, a cover plate enclosing the top of the retort at the front thereof, an annular plate mounted thereon spaced from said plate and the upper interior portion of the fire box, there being ports between said cover plate and annular plate for the exit of said air passing around the retort, and ports between said annular plate and the top of the fire box for the exit of air passing around the plate between it and the fire box.

15. In combination in a boiler of a retort, a

fire box" for supporting the retort, tuyres supported therein, means of delivering air on the sides of the retort partially through the tuyeres above the retort, means of returning a portion of said air from the inner end of the retort beneath it to a point at the front of the retort beneath it, and means of passing the air around the retort at the front and discharging it at the front above the retort into the fire box.

16. In combination in a boiler of a retort, a' fire box for supporting the retort, tuyeres supported therein, means of delivering air on the said means discharging air directly above the fuel in the retort and another portion at the top of the fire box directly beneath the front end thereof.

17. In combination in a boiler, a circular fire box mounted therein, a retort therein having the bottom thereof spaced from the fire box, tuyeres mounted on the sides and inner end ofsaid retort, an end plate on the retort, a bridge Wall transversely arranged in association with the end plate and the inner end of the retort, spacers betweenthe retort, tuyeres and firebox to form air chambers for delivering the air through the tuyeres and beneath the retort, means for returning said air from the rearof the retort beneath it to the front thereof, and means for distributing it in an annular path at the front of the retort. 1 c I '18. In combination in a boiler, a-circular fire box mounted therein, a retort therein having the bottom thereof spaced fromthe fire box, tuyres mounted on the sides and'inner end of said retort, an end plate on the reto1't,'a bridge wall transversely arranged in association with the end plate and the inner end of the retort, spacers between the retort, tuyeres and firebox to form air chambers for delivering the air through the tuyeres and beneath the retort, means for returning said air' from tht rear of the retort beneath it to the front thereof, means for distribut ing'it in an annular path at the front of the retort, a part of it just above the retort and a part of it just beneath the top of the fire box.

19. In combinationin a boiler, a fire box of circular form, a retort resting therein and spaced therefrom, tuyeres having interlocking shoulders mounted on the marginsof said retort, their outer ends resting on the inside of the fire box, arcuate spacer plates spaced from the fire box having flanges engaging depending shoulders on the tuyeres and the lower sides of the retort, an

having fianges engaging depending shoulders on the tuyeres and the lower sides of the retort, an end plate on the retort having shoulders for supporting said arcuate spacer plates. a detachable bracket for a bridge wall associated with said end plate, a bridge wall, a detachable retaining plate supporting said arcuate spacer plates, a detachr around the front of the retort and at points above retaining the bridge wall and associated with the end plate. j

21. In combination in a boiler, a fire box of circular. form, a retort resting therein and spaced therefrom, tuyeres having interlocking shoulders mounted'on the margins of said retort, their outer ends resting on the inside of thefirebox, arcuate spacer plates spaced fromthe fire box having flanges engaging depending shoulders on the tuyeres and the lower sides of the retort, an end plate on the retort having shoulders for sup-, porting said arcuate spacer plates, 1a detachable bracket for a bridge wall associated with said end plate, a bridge wall, a" detachable retaining plate retaining the bridge wall and associated with the endplate, and an air chamber com municating with the space beneath the 'tuyres formedbetween the end of the retort andthe end plate whereby air is deliveredbeneath the retort from the rear end thereof to the front thereof. V,

22. In combination in a boiler, a fire box of circular form, aretort resting'therein and spaced therefrom, tuyeres having interlocking shoulders mounted on the margins of said retort, their outer ends resting on the inside of the fire box, arcuate spacer. plates spaced fromthe fire "box having flanges engaging depending shoulders on the tuyeres and the lower sides of the retort, an end plate on the retort having shoulders for able bracket for abridge wall associated with said end plate, a bridge wall, a detachable retaining plate retaining the bridge wall and associated with the end plate, and an air chamber communicating with the space beneath the tuyeres formed between the end of the retort and the end plate whereby air is delivered beneath the retort from the rear end thereof to'the-front thereof, and means for distributing said air the retort at the front thereof.

23. In combination in a boiler, a fire box, a retort therein forming with the fire box bottom an air passageway, tuyeres mounted on said retort and extending to the walls of the fire box forming chambers on either side of the retort between it, the fire box wall and the tuyeres, and means of delivering air to said chambers and from the chambers to the rear end of the air passageway.

24. In combination in a retort therein forming with the fire box bottom an air passageway, tuyres mounted on said retort and extending to the walls of the fire box forming chambers on either side of the retort between it, the fire box wall and the tuyeres, means of delivering air to said chambers and from the chambers to the rear end of the air passageway, and means of balancing and proportioning the air delivered to the respective chambers on either side of the retort.

25. In combination in a boiler, a firebox, a retort therein, tuyeres mounted on said retort and extending to the walls of the fire box forming chambers on either side of the retort between it,

.respective chambers on either side of the retort, and means of returning the air not delivered through the tuyeres from the inner end ofthe retort beneath it to a point at the front of the fire box.

26. In combination in a boiler, a fire box, a reboiler, a fire box, a

tort therein, tuyeres mounted on said retort and extending to thewalls of the fire box forming chambers on either side -o'fthe retort between it, the fire box and the tuyr'es, means ofdeliver ing air t'o-s'aid 'chambersand' means of balancing and proportionin'g'the airdelivered" to the respective chambers on either" side of the retort,

and means of returning the air not delivered through'the tuyeres'frorn the innerend of the retort beneath itto a pointjat -the front ofthe' fire box, and means of distributing said air "in an 'annular path adjacent the interior of the fire box andi dischariging -it' inwardly adjacent'the' front thereof. I i

27. In combination in a;boilena ci'rcularfire box therein, a retort mounted upon the bottom of the fire having its bottom s'paced' from thefire box, a reciprocating pusher'carried'ln said retort forming a portion of the bottom thereof, a tapered end wall in the retort, al'spaced end plate, tuyres mounted onthe'upper edgesof said retort having air openings discharging thereover, and inner depressed upper surfacesfor forming refuse pits, a bridge wall associated with said end pla'te'extending' across said tuyeres and. refuse pits. i j

'28. In combination a boiler, a circular fire box 7 therein, a retort mounted uponthe bottom of the fire box having as beaom spaced" from the fire box, a reciprocating pusher carried in said retort forming a portion of the bottom thereof, a tapered end wall in the retort, a spaced end plate, 'tuyres. mounted on the; upper edges of said retort having air openings discharging thereover, and inner depressed upper surfaces for forming refuse pits, a bridge wall associated with said end plate extending across said tuyeres and refuse pits, and a common aligning means carried by said boiler extending through .said fire box and said tuyeres to said end plate for supporting and aligning said tuyeres.

29. In combination, a circular fire-box, a retort resting on the bottom thereof and forming with the bottom an air passageway, tuyeres extending from the top of the retort to opposite sides of the fire box, and forming with the fire box air chambersconnected to the rear end of the air passageway, said several parts occupying approximately one-half of the circular space in the fire box.

end of the retort resting upon it and extend ing across it,and annular sections spaced from said bridge plate and the upper half of said fire box providing an annular'passageway between it and the fire box, and reciprocating means in said retort forming the-bottom thereof for delivering fuel therethrough and therefrom.

31. In astoker, a boiler, a fire box disposed therein, a retort inthe fire box, air delivery passageways on either side of, theretort to the end thereof, said retort forming with the fire box a return'passagewayto thefront of the firebox communicating with the passageways, a cover plate for said retort, filler plates associated therewith, spaced annular plates arranged above the retort within the fire box having outlet openings adjacent their interior margins along' the interior of the fire box, and means for permitting the communication of the return air. therewith through the walls of :the retort from a point beneaththe retort whereby the return air is deliveredover the retort and within the upper half of the fire box; adjacent the wall thereof.

; .32. In a stoker, a boiler, a fire box disposed therein, a-retort in the fire box, air delivery, passageways on either side of the retort to the end thereof, said retort formingwith the fire box a return passageway to the front of the fire box communicating with the passageways, a cover plate for said retort, filler plates associated therewith, spaced annular plates arranged above the retort within the fire box havingoutlet openings adjacent their interior margins along the 'interiorof thefire box, and means for per-,

mitting the communication of the return air therewiththrough the walls of the retort from a pointbeneath the retort whereby the return airgis delivered over the retort and within the upperhalfof the fire box adjacent the wall 7 thereof, and rivets for joining said firebox and boiler, the interior of which are cooled by said 7 returning air. j 1 33. In combination, a circular fire box, a retortresting therein, air passageways on either side thereof, the tops of which passageways are formed at one end by filler blocks, a'spacedcover plate resting on said retortand spaced from said filler blocks to permit air to circulate' beneath the filler blocks from the air passageways, means at the inner end of said retort for returning air therebe'neath to the forward endthereof, means at the bottom of said'forward end of the retort for discharging air into annular p'assageways'beneath said first mentioned passageways and ex- 7 tending upwardly and completely around them]- terior of the fire box, said annular passageway having discharge ports adjacent the fire box above the filler blocks.

34. In combination, a fire box, a, retort there,-

in, lateral air passageways, tuyres supported between the fire box and the retort for laterally retort, and an annular passageway communicating with the front and bottom of the retort for the delivery of said return air within the annular front'margin of the fire box, and'means of discharging said air within the fire box in an annular stream above the filler block. A

HARRY M. SWINDLER. 

